WASHINGTON (AP) — U.S. health officials on Tuesday approved a plan to increase the country’s limited supply of the monkeypox vaccine by giving people just one-fifth the usual dose, citing research that shows that a lower amount is almost as effective.
The so-called dose-response approach also envisages giving the GenoS vaccine using injections under the skin rather than into deep tissue — a practice that is better at modulating the immune system. Recipients will continue to receive two shots within four weeks.
The highly unusual move is a clear acknowledgment that the US currently lacks the supplies needed to vaccinate everyone seeking protection from the fast-spreading virus.
That includes the 1.6 to 1.7 million Americans considered by federal officials to be most at risk from the disease, mostly males or males with HIV who are at high risk of contracting it. To vaccinate this group would require more than 3.2 million vaccinations.
White House officials said the new policy would immediately multiply the 440,000 available as full cans into more than 2 million smaller cans.
“It’s safe, it’s effective and it will significantly increase the amount of vaccine doses available to communities across the country,” Robert Fenton, White House coordinator for monkeypox control, told reporters.
The Biden administration last week declared monkeypox a public health emergency to slow the growing outbreak that has infected more than 8,900 Americans. Officials on Tuesday announced a separate provision that would allow the Food and Drug Administration to expedite reviews of medicinal products or new uses for them, such as: B. Dose-saving techniques for Genios.
The FDA approved the new approach for adults 18 and older who are at high risk of monkeypox infection. Young people can also get the vaccine if they’re considered high-risk, the agency said, although they should get conventional injections.
FDA officials emphasized that the second dose is important to ensure safety.
dr Peter Marks of the FDA said, “We strongly believe that two doses are necessary because in part we don’t have evidence that people are adequately protected from a single dose at three, six, eight months.” Will go.” vaccination chief.
Regulators pointed to a 2015 study that showed vaccination with a fifth of the traditional two-dose vaccine elicited a stronger immune system response than the full dose. According to the study, funded by the National Institutes of Health, about 94% of people who received the small dose had adequate levels of virus-fighting antibodies, while 98% of people who received the full dose had adequate levels of antibodies.
The NIH plans to continue testing the technology in the coming months. And Rochelle Valensky, director of the Centers for Disease Control and Prevention, said her agency is already beginning to track real-world effectiveness in American communities, although it will take time to produce initial estimates.
However, some experts and advocates feared that with little data to support the directive, reducing the vaccine’s effectiveness could backfire.
David Harvey of the National Coalition of STD Directors said: “We have serious concerns about the limited amount of research that has been done on this dosing and administration method and we fear it will give people a false sense of confidence that they are safe. “, in a statement.
Smaller doses also require a different type of injection that only penetrates the top layer of skin and not the bottom layer between the skin and muscle. This is a less common technique that may require training for some healthcare practitioners. It is also associated with more side effects like redness, itching, and swelling.
Shallow injections are believed to help stimulate the immune system because the skin contains many immune cells that target outside invaders.
CDC will provide training materials on this technology as well as a broad awareness campaign for US health officials.
Rationing doses of the vaccine is common in Africa and other parts of the world with limited health resources. In recent years, the World Health Organization has endorsed the approach to combating outbreaks of yellow fever, polio and other diseases.
“This is not an unusual situation,” said Dr. William Moss of the Johns Hopkins Vaccine Access Center. “It comes down to public health decision-making: In the middle of an outbreak where you don’t have enough supplies, are you making that compromise?”
Both the UK and Canada have adopted a single-dose vaccine strategy, prioritizing those most at risk of monkeypox. And public health departments in several major US cities, including New York, San Francisco and Washington, followed a similar strategy in the face of limited supplies.
US officials have shipped more than 617,000 full doses of vaccine to state and local health authorities. So far, the shots have been recommended for people who have been exposed to monkeypox or are likely to have been caused by recent sexual contact in areas where the virus is spreading.
The Biden administration has come under fire for not quickly removing millions more doses from the country’s strategic national stockpile. Officials have ordered 5 million shots since July, but most are not expected to be delivered until 2023. With the new dosing strategy, that would represent 25 million doses.
The US government owns the bulk of the vaccine material, equivalent to 16.1 million doses, under a deal with Danish manufacturer Bavarian Nordic. But the contents have to be sealed into vials, a process that is expected to take months as the small company orders from other countries.
The FDA approved the Genoace vaccine for the prevention of smallpox and monkeypox in 2019, in part based on studies in monkeys. According to the FDA label, animals that received a two-dose vaccine were more than twice as likely to survive after contracting monkeypox as those that didn’t.
Additional human studies have shown that people who received Zynos had an immune response similar to those who received the chronic smallpox vaccine. But Genios has not been tested on humans with either monkeypox or the related smallpox that was eradicated decades ago.
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